Sanding machine



Aug. 6, 1946. J. ROBINSON, JR

- SANDING MACHINE 4 Sheets-Sheet- 1 Filed Nov. 2, 1945 g 1946- Y J. ROBINSON; JR I 2,405,328

SANDING MACHINE Filed NOV. 2, 1945 4 Sheets-Sheet 2 gwue/wbom Jim? j D Aug. 6,1946 J. ROBINSON, JR 2,405,328

SANDING MACHINE Filed Nov. 2, 1945 4 Sheets-Sheet '3 Q I 3mm J $597k fidfiilzfam 9 5 @Q I Wow;

1946- J. ROBINSON, JR 2,405,328

SANDING MACHINE Filed Nov. 2; 1945 4 Sheets-Sheet 4 (Ittornegs Patented Aug. 6, 194-6 SANDING MACHINE Joseph Robinson, Jr., Dover, Ohio, assignor to Marsh Wall Products, I

v poration of Ohio 110., Dover, Ohio, a cor- Application November 2, 1945, Serial No. 626,237 15 Claims. (or. 1-78) The invention relates to sanding machines and more particularly to certain improvements upon my co-pending application, Serial No. 587,924, filed April 12, 1945. This type of sanding ma chine was especially designed for sanding wall panels and the like, comprising a fiat board or panel of pressed fibre board such as Masonite, or other suitable material, coated with several coats of paint or enamel.

In the manufacture of these wall panels, the surface of the board is first coated with a thin prime coat of paint or enamel which after dry,- ing or curing is thoroughly sanded before the finish coat or coats are applied, the sanding being necessarily light enough so as not to cut through the prime coat at any point and yet suiiiciently firm to remove any small projections or bumps caused by particles of dust or dirt which may have fallen upon the board before it is coated, or which may have adhered to the prime coat before it has dried.

Owing to the fact that there were no sanding machines which had been found to be satisfactory for this sanding operation, it had been necessary to perform the same by hand, until I developed the sanding machine forming the subject matter of my aforesaid application, Serial No. 587,924.

This sanding machine comprises generally a table over which the wall panel is moved beneath a rotating sanding drum having pairs of spaced brushes around its periphery and having sand paper located over each spaced pair of brushes and. spanning the space therebetween.

This type of sanding machine is now in use thoroughly sand any thin portion of the board or the portions of the sand paper in use become worn. v

It is known that machines'have been-designed to automatically feed the sand paper, or other .abrasive surface finishing material, around the periphery of thedrum so as to continuously .pre sent new portionsof the sand paper to the work, but in such machines the feeding of the sand paper around the periphery of the drum is automatically controlled by the rotation of the drum itself. This may result in a considerable waste of sandpaper as the feeding mechanism will operate continuously durin the rotation of the drum regardless of whether or not Work is being passed through the machine.

The object of the present improvement is to provide means controlled by the wall panels or other work passing through the sanding machine for feeding the sand paper around the periphery of the sandingdrum and over the spaced pairs of flexible brushes thereon. i

Another object is to provide a sanding machine of the character referred to inwhich. the wall panels, or boards, are passed over a table beneath the sanding drum, the panel or. board being moved across the table by means of a pair of spaced rolls contacting opposite surfaces of the board, one of said rolls being driven and the other roll being rotated by the movement of the panel upon the table and controlling mechanism which automatically feeds the sand paper around the periphery of the sanding drum.

A further obiectis the provision of a sanding machine ofthis character in which the mechanism which feeds the sand paper around the drum includes an instantaneous switch whichis intermittently operated by the passing of the wall panels through the machine, each operation of said instantaneous switch causing a movement of the sand paper feedingmechanism.

A still further object is the provision of a machine of this character in which the instantaneous switch energizes a solenoid which operates the sand paper feeding mechanism upon the drum.

Another object of the invention is the provision of a machine of this character in which the sand paper is .fed aroundthe drum by means of a pair of friction rolls engaging opposite end portions of the strip of sand paper and simultaneously driven in the same direction through mechanism operated by the solenoid,

The above objects, together with others which will be apparent from the drawings and following description, or which may be later referred sanding machine in the manner illustrated in the accompanying drawings, in which;

Figure 1 is a front elevation of a sanding machine embodying the invention, with parts broken away for the purpose of illustration;

Fig. 2 an end elevation of the sanding machine shown inFig. 1, parts being broken away to show the interior of the machine;

Fig. 3 an end elevation of the sandin drum on a much larger scale;

Fig. 4 a fragmentary, detail elevationof the mechanism for intermittently operating the sand paper feeding rolls;

Fig. 5 a section taken as on Fig. 4;

Fig. 6 an enlarged detail elevation of the work operated roll and the mechanism controlled thereby for operating the instantaneous switch;

Fig. 7 a view similar to Fig. 4 showing a modified form of sand paper feeding mechanism; and Fig. 8 a fragmentary, detail sectional view of the bearing portion of one of the rollers upon the drum underrwhich the sheet of sand paper is located.

The improved machineis illustrated in the accompanying drawings as comprising substantially the sanding machine disclosed and claimed in my pending application, Serial No. 587,924, above referred to, with the additions of the said paper feeding mechanism to which the present application more particularly pertains.

The machine may be supported upon the uprights or legs l located at the corners of the machine and braced as by the cross bars .I l horizontal frame members I2 being connected to the upper ends of the uprights.

The sanding drum is indicated generally at 13 and fixed upon a shaft 14 journalled in bearings iat opposite ends of the frame. On opposite sides of the drum are located the feed rolls l6 and I1 joumalled in bearings 18 mounted upon the frame members.

' To compensate for boards or panels of different thicknesses, the table I3 over which the panel or boards are arranged to be slidably moved beneath the drum, may be vertically adjustably mounted upon the uprights ID, by means of the sliding frame members 20 adapted to be held in adjusted position as by the clamping screws 2!.

Rolls 22 and 23 are journalled in said sliding frame and adapted to cooperate with the upper rolls [6 and H to feed the panels or boards, indicated generally at B, through the machine and beneath the drum 13.

A hood 24 may be located over the entire top of the machine and connected to an exhaust pipe 25 through which all dust may be removed by suction.

A hold down device may be provided for holding the board or panel down upon the table as it passes through the machine and may comprise a board 26 of slightly flexible material hingedly connected at its upper end to one side of the hood as at 21, the free end of the hold down board being'held down against the top surface of the panel or board as by the spring 28.

The sanding drum, indicated generally at I3. is shown in detail in Fig. 3 and may be of polygthe line 5-5,

onal form having" the spaced projecting portions 29 terminating in the fiat tangential surfaces 33. A channel member 3| is shown fixed upon each flat surface 30 and extends longitudinally throughout the length of the drum and a spaced pair of elongated, flat brushes is mounted there- 4 in comprising the flexible bristles 32 located in channel frames 33 and extending longitudinally through the length of the drum.

Elongated blocks 34 may be provided for clamping each spaced pair of flat brushes within its channel holder 3| and arranged to be forced apart and against the brushes as by a wedge strip 35 drawn down into place by screws 36.

A strip or sheet of sand paper, indicated generally at S, of a width substantially the length of the drum, is placed entirely around the drum over the ends of the bristles 32 and under the 7 rolls or rods?! in the manner shown in Fig. 3.

These rolls 31', are of the same length as the drum and their end portions are journalled as indicated at 37' upon the radially disposed adjusting members 38 which may be radially adjustably connected to the heads 39 at the ends of the drum as by the screws 40 and slots 4|, so that any desired tension may be placed upon the sheetof sand paper by radially adjusting these rolls within the recessed portions 42 of the drum.

Each end of the sand paper. strip or sheet may be frictionally engaged between one of the friction rollers 43 and the cooperating flange or plate 44. By rotating both of the rollers 43 in the same direction, it will be seen that the sand paper will be moved circumferentially around the entire drum, feeding the leading edge of the sand paper inward between one roll 43 and its corresponding plate 44, while the other end of the paper is fed outward between the other roll and its plate.

As shown in Fig. 3, with the two rolls 43 rotating in the directions of the arrows, the leading end L of the sand paper will be fed inward while the opposite end portion 0 will be simultaneously fed outward.

For the purpose of operating these rolls, a worm gear 45 is fixed upon one outer end of each roll 43 and meshes with a worm screw 46, the shaft 41 of which is journalled in bearings 48 mounted upon the adjacent head 39 of the drum.

A ratchet wheel 49 is fixed upon each worm screw shaft 41 and is engaged bya pawl 50 pivoted as at 5| upon a sleeve 52 slidably keyed upon the shaft l4 of the drum as indicatedat 53.

The sleeve 52 is provided with an annular groove 54 which receives a yoke 55 formed upon one end of the arm 56 which is fixed upon one end of the armature 51 of the solenoid 58 which is fixedly mounted through the adjacent bearing bracket l5 for the drum shaft l4.

It will be seen that as the solenoid 58 is energized the armature 5'! thereof will be reciprocated outward, or to the left as viewed in Figs. 1 and 4, and through the yoke 55. the sleev 52 will be'correspondingly moved to the left causing the pawls 50 to rotate the ratchets 49 in the direction of the arrow shown in Fig. 5 a distance of one tooth. As the solenoid is de-energized the spring 59 will return the armature 51, arm 56 and sleeve 52 to the normal position as shown in Figs. 4 and 5.

With each movement of the sleeve 52 as above described, the worm screw 46 will be given a slight turning movement and through the worm gears 45 the rolls 43 will be rotated in unison in the direction of the arrows shown in Fig. 3.

For the purpose of intermittently energizing the solenoid 58 attention is called to the mechanism shown in detail in Fig. 6 and also illustrated in Figs. 1 and 2. The shaft 60 of the roll 22 is operatively connected to reduction gearing (not shown) located within the gear housing 6|. This reduction gearing may be of any usual or well known design and as the particular type of gearing does not in itself form any part of the invention, but is merely provided for reducing the speed of the pulley 62 relative to that of the roller 22, it is not thought necessary to illustrate the gearing.

The pulley 62 is shown operatively connected, as by a belt 63, with a pulley 64. A stud 65 is fixed upon one side of the pulley 64 and adapted to contact the finger or button 66 upon the instantaneous switch 61 once in each complete revolution of the pulley 54. The instantaneous switch 6'! is located in a suitable electric circuit (not shown) and connected by the wires 68 with the solenoid 58.

Thus as the wall panels or boards are fed through the machine the roll 22 will be rotated thereby and through the reduction gearing in the housing 6|, the pulley 64 will be slowly rotated each complete revolution thereof operating the instantaneous switch .61 to energize the solenoid 58 and through the mechanism shown in Figs. 4 and 6, and above described in detail, the rolls 43 will be given a slight rotation to feed the sand paper around the circumference of the sanding drum, presenting new surfaces of sand paper to the work as the portions thereof in use become worn.

For the purpose of driving the drum l3 and roll IS in the direction of the arrows shown on Fig. 2, pulleys 69 and Hi, or their equivalents, may be fastened upon the shafts of the drum and roll respectively for connection to any suitable driving means. Both the drum and the fed roll may be rotated at the desired speed. very satisfactory results being obtained in actual practic by rotating the drum at approximately 700 revolutions per minute and. the feed roll at a proper surface speed to move the boards or panels about 25 feet per minute.

With the drum rotating at the proper speed in clockwise direction, as viewed in Figs. 2 and 3, and the wall panels or boards moving at the proper rate of speed from left to right, as viewed in said figures, the surface of the board or panel being sanded will be intermittently contacted in rapid succession by the portions of the sand paper located over the several spaced pairs of brushes and spanning the space between the brushes of each pair.

Referring to Fig. 3, it will be obvious that when the drum is rapidly rotated these portions of sand paper, stretched between the brushes of each pair as indicatedat C, will be thrown outward by centrifugal force.

As each of these portions of sand paper contacts the surface of the board or panel, they will be flexed slightly inward. If a high point of the board is encountered, the flexibility of the brushes and the portion of the sand paper spanning the space between the brushes of each pair will compensate for the same, the sand paper being flexed inward and the brushes 32 being slightly flexed as shown at the bottom of Fig. 3.

When a low point of the board is encountered, the sand paper will contact the same as it is fiexed outward due to centrifugal force. Thus it will be seen that all portions of the surface of a board will be properly sanded, the construction compensating for any variations in thickness in the board.

In Fig. '7 is shown a slight modification of the mechanism operated by the solenoid which intermittently rotates the worm gears 46. In this form of the invention, the rolls 43, worm gears 45 and worm screws 46 may be the same as shown in Figs. 3 and 4 and the same reference numerals are applied thereto in Fig. 7. However, instead of fixing a ratchet upon the end of each worm screw shaft 41, a beveled pinion H is fixed upon each of these shafts and meshes with a bevel gear 12, rotatable relative to the shaft l4 and held in mesh with the pinion H as by a collar 13 fixed upon the shaft.

The sleeve 52a is .slidably keyed upon the shaft l4 and arranged to be operated by the yoke 55 upon the arm 56 which is fixed upon the armature of the solenoid in the same manner as shown in Fig. 4. The sleeve 52a comprises a clutch member having the friction surface 14 adapted to be moved into frictional contact with the rear side of th beveled gear 12 when the solenoid is energized, causing the beveled gear to rotate with the shaft I4 and through the beveled pinion H to give a slight turning movement to the worm screws 46. Otherwise the operation of this sand paper feed mechanism is the same as that shown in Fig. 4.

From the above it will be obvious that the sand paper will be automatically fed circumferentially around the drum, presenting new portions of the sand paper to the work as the portions in use become worn, the feed mechanism being controlled by the movement of th wall panels or boards through the machine so that the sand paper will be fed around the drum at the proper speed to accommodate the amount of work passing through the machine and so as not to change the adjustment of the sand paper excepting when work is passing through the machine. 1

Thus it will be seen that the sanding drum may continue to operate for a considerable period of tim during which no boards are passed through the machine without changing the adjustment of the sand paper and causing any waste of sand paper.

I claim:

1. A surface finishing machine including arotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material and means controlled by the movement of the work for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum.

2. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material and means controlled by the movement of the work for intermittently operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum.

3. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, and means controlled by the movement of'the workfor operatingsaid roll operating means. i "4. A'surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, and means controlled by the movement of the work for intermittentlyoperating'said roll operating means. 5. A surface finishing machine including a rotating drum, a sheet of fiexible'surface finishing material located around said drum, 7 a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by the movement of the work for energizing said solenoid.

6 A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end por tions of said sheet of surface finishing material, means for moving work through the machine'in contact withthesurfacefinis'hing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by the movement of the work for intermittently energizing said solenoid.

'7. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means upon the drum for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by the movement of the work for energizing said solenoid.

8. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end por tions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means upon the drum for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by the movement of the work for intermittently energizing said solenoid.

9. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, worm gear means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said worm gear means, and means controlled by the movement of the work for energizing said solenoid.

10. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material around the drum, a solenoid for operating said roll operating means, an instantaneous switch for energizing said solenoid, and means controlled by the movement of the work for operating said instantaneous switch.

11. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an Luiwinding' roll engaging opposite end portions of said sheet of surface finishing material, means for moving work through the machine in contact with the surface finishing material, meansfor operating the winding roll and unwinding roll for moving the sheet of surface finishing material around the drum, a solenoid for operating said roll operating means, an instantaneous switch for energizing said solenoid, and means controlled by the movement of the work for intermittently operating said instantaneous switch.

12. A surface finishing machine including a rotating drum, 2. sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, a driving roll and a cooperating work driven roll for moving work through the machine in contact with the surface finishing material, and means controlled by said work driven roll for operatin the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum.

13. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, a driving roll and a cooperating work driven roll for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by said work driven roll for energizing said solenoid.

14." A surface finishing machine including a rotating drum, a sheet of flexible surface finishing material located around said drum, a winding roll and an unwinding roll engaging opposite end portions of said sheet of surface finishing material, a driving roll and a cooperatingwork driven roll for moving work through the machine in contact with the surface finishing material, means for operating the winding roll and unwinding roll for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, and means controlled by said work driven roll for intermittently energizing said solenoid.

15. A surface finishing machine including a rotating drum, a sheet of flexible surface finishing 10 for moving the sheet of surface finishing material circumferentially around the drum, a solenoid for operating said roll operating means, an instantaneous switch for energizing said solenoid, and means controlled by said work driven roll for operating said instantaneous switch.

JOSEPH ROBINSON, J R. 

